Process for making an insecticide



here disclosed provides a satisfactory substitute Patented Feb. 1, 1938 UNITED STATE PROCESS FOR MAKING AN INSECTICIDE Louis N. Markwood, Washington, D.'C., dedicated to the free use of the People oi the United States of America No Drawing. Refiled for abandoned application Serial No. 744,636, September 19, 1934.

This

application June 24, 1937, Serial No. 150,165 I 1 Claim. (01. 167 34) &

(Granted under the act of March 3, 1883.. as amended April 30, 1928; 370 0. G. 757) This application is a refile of my abandoned application, Serial No. 744,636, filed on September 19, 1934.

This application is made under the act approved March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed may be manufactured and used-byv uble compounds has been known and used for many years as an insecticide. The object of this 'inventionis to make a nicotine insecticide wherein the nicotine, suitable combined with othe bodies, is held or' fixed in substantially waterinsoluble form. By insoluble form is here meant .of such a low degree of solubility that the nicotine is retained on sprayed surfaces of fruits, vegetables and vegetation over a long period of time under the usual conditions of moisture and temperature.

Nicotine insecticides in water-soluble form suffer from the disadvantage, first, that they do not remain permanently on sprayed surfaces--either running off during application or being washed oil by rain water,and secondly, that their use is limited to soft-bodied (sucking) insects which are killed only by external contact with the soluble form of nicotine. One advantage possessed by the product here disclosed is that, being insoluble, it is not washed oil by rain water and so is effective over long periods of time. Another advantage is that it is effective against a large and economically important group of insects known as chewing insects which can be killed or controlled only as they consume internally the poisonous matter.

Still another advantage is that the product ceous compounds as well as some inert matter in the form of sand and other earthy constituents. It is usually mildly acid. It is widely and abundantly distributed throughout the United States and is available at a very low price. Presentuses 5 of 'peat consume only a fraction of the known supply and any new uses would be welcomed by agricultural industry.

The reaction product of nicotine and peat can be applied as a fine dust to the vegetation desired to be protected, or item be suspended in water, with or without addition of other substances, and applied as a spray in a dosage dependent upon the nicotine content.

In making the nicotine-peat product I may proceed as follows: To an aqueous solution of nicotine in the free state I add a quantity ofground peat so as to make a thin, suspension. After shaking well and preferably with continuous agitation I allow the mixture to stand up to 2 hours at ordinary or elevated temperature. Then I separate the solid material from the aqueous liquid by known means such as filtration and wash the solid cake well with water until the liquid is neutral to an indicator such as phenolphthalein and contains only a minor quantity of soluble nicotine, as shown by a slight 1 opalscence with silicotungstic acid. Then the material is ready for use in spray form, or itmay be dried under mild heat and be stored, 3o transported or used in the drystate. Any unused nicotine which is found in the liquid porlation. However, I may take as little as 1% gm. 40 v of nicotine or asmuchas 10 gms., from 10 cc. of water to 100 'cc., from 1% gm. of peat to 15 gms. As long as nicotine and peat are present in any quantity there is combination resulting for insecticides containing arsenic, fluorine and metallic compounds, the use of which is generally regarded as fraught with danger to the public health.

I have found that nicotine when reacted with peat yields'a product in which the nicotine is.

in an insoluble nicotine-peat product of the nature disclosed.

, bined is greater under that condition, than is .the case at lower temperatures. However, the

reaction-proceeds at temperatures down to the freezing point of the liquid. It also proceeds at temperatures up to 200 0., under pressure, but again the yield is lower.

The time allowed for reaction is generally 2 hours, but the same results are achieved in as little as 15 minutes.

I may also proceed as follows: Into a mass of air-dry peat suitably contained I pass the vapor of nicotine or a mixture of the vapors of nicotine and of water. Or I pass the vapor of nicotine or a mixture of the vapors of nicotine and of water into a suspension of peat and water.

It is found that 1 gm. of a given peat combines with a more or less constant quantity of nicotine. Thus, under the usualconditionsoutlined above- A.; gm. of nicotine, 25 cc. of water, and 1 gm. of peat, on the steam bath for 2 hours-the percentage of nicotine in the well washed product was, in the case of a Florida peat, 4.7. In the case of a Michigan peat the percentage was -8.2. Recognition is made of the fact that peats of different vegetable origin or derived from different localities vary in combining power.

I have found further that when peat is given 6.9% of nicotine when previously treated with 3% acetic acid. In all cases where peat is given a preliminary treatment it is washed well to remove excess acid and dissolved matter as otherwise the percentage of combined nicotine is low ered. ,Thus, in thepresence of 0.2 cc. of acetic acid in a volume of 25 cc. of a 2% nicotine solution the percentage of nicotine combined with 1 gram of Florida peat is reduced to 3.7, from 4.7; in the presence of 0.5 cc. of acetic acid it is further reduced to 2.2.

It will be recognized that nicotine in the presence of acetic acid is equivalent to an aqueous solution of a nicotine salt, viz., the acetate. Nicotine hydrochloride, formed from nicotine and hydrochloric acid, also reacts .with peat. Thus, inthe presence of 6 cc. of NHCl in a solution of 25 cc. of a 2% nicotine solution the percentage of nicotine combined with 1 gram of Florida peat is 2.7. It is apparent that while nicotine salts react with peat the extent of combination isnot as great as with-free nicotine. A

I have found also that when peat is given a preliminary treatment with a fixed alkali before the reaction with nicotine the percentage of the latter combined in the peat is greater than when the peatis not so treated. Thus, the Florida peat after previous treatment with a 5% NaOH solution followed by-thorough washing, first with water and then with very dilute acid, contains 9.5% of nicotine.

Peat that has been treated with ammonia (socalled ammoniated" peat) also reacts with nicotine. Thus, an ammoniated peat containing 11.8% of nitrogen held 2.6% of nicotine.

Having thus described my invention, what I claim for Letters Patent is: In a process for preparing nicotine-peat reaction products, the steps which comprise treat- LOUIS N. MARKWOOD. 

